Research Of Asynchronous Motor Vector Control Variable Frequency Regulating System

In view of the current situation of three-phase AC asynchronous motor speed control, analyzed the principle of three-phase asynchronous motor vector control variable frequency speed regulation system, and proposed a hybrid magnetic field calculation method, realized three-phase AC asynchronous motor in rotor field-oriented decoupling control, had a good dynamic response performance.In the aspect of rotor magnetic field measurement, for the advantages and disadvantages of the traditional voltage model and current model, hybrid model is used to give full play to the advantages of the current type and voltage type. When the speed is low, using the current model and the speed is medium, using the mixed mode, while the speed is high, using the voltage model to measure the magnetic field. Magnetic field of the hybrid model refers to take the average value of the results calculated by current model and voltage model while the rotor speed is in the middle of the transition zone.In the aspect of hardware, put the TMS320F2812as the core control chip of system to construct three phase asynchronous motor vector control system hardware platform. The hardware circuit includes AC-DC-AC circuit, DSP control circuit, signal detection circuit, etc. AC-DC-AC circuit consists of diode uncontrollable rectifier circuit, intermediate dc filter circuit and three-phase full bridge inverter circuit. In order to effectively suppress spike pulse generated at the moment of IGBT shut off, pay more attention to the circuit design of IGBT snubber circuit.In the aspect of software, using C language to development and debugging vector control system of DSP program in the CCStudio v3.3environment. The DSP program consists of the main program and the PWM interrupt program, which is the core module of vector control. PWM interrupt program including stator current and voltage detection module, the rotor speed detection module, flux measurement module, SVPWM module and serial interface communication module. The DSP program has the characteristics of high efficiency, compact, easy to read. In order to manipulate DSP easily and monitor the motor parameters, using LAB VIEW to develop the speed control system of PC software.Finally, using MATLAB to simulate the current model and the voltage model, by comparing the simulation results concluded their advantages and disadvantages. Based on merits and demerits of the two models, this article puts forward a hybrid magnetic chain model. It’s also by using the simulation contrast methods to verify the conclusion that the hybrid model of flux value in the medium speed area is more closer to the actual valve. In addition, three-phase asynchronous motor in the rotor magnetic field orientation vector control system simulation model is set up, by comparing the simulation results under different working conditions to verify the superior performance of three-phase asynchronous motor vector control system.